The intent is to have the femurs sit with the tibia servo flat to the ground, which will adjust the loading angle on the servo you mention to be more of an inline pull and less of a twisting torque....

One alternative to a logic analyzer would be to take a three wide set of female headers, and attach LED's to the signal and ground of each digitalIO you are using for debug. It would then be like one...

So, I extended the tibias with some aluminum bar, and that fixed the bobbing entirely. Now I have to decide if it is safe to bring liftHeight above the stock 30 to deal with the legs not clearing the...